Mapping an Earthlike planet

[Akubra]

Thanks Pixie. I'm planning to make one more major revision (I know it'll never be really final, of course) to correct these things, and then it's about time to move on. The climate map is still waiting. I've been postponing it for some time now. Hopefully I'll find the courage to continue working on it in the coming days.

Cheers - Akubra

[Akubra]

I finally managed to get my tectonics done. I tried to be as complete and correct as possible. These are the boundaries I reworked:

• The southern and northwestern boundaries of Tabinoth plate
• The boundary between Eneaga and Yirral plates
• The boundary between Eneaga and Sulina / Ghatia / Taiunta plates (with the long island arc)
• The boundary between Ranineo and Otaia / Ghaon / Arumanthi plates
• The boundary between Lomo and Ranineo / Arumanthi plates

In order to get the direction of subduction right I created a few additional small plates:

• Agehoni and Utoni plates (off Eneaga)
• Sira plate (off Ranineo)

I also broke off two other plates off Eneaga (Rantaia and Irumi plates) to create a new subduction zone between it and East Nohhon plate and some volcanic activity in the west of the continent. In the process I also moved the continent of Eneaga slightly to the northwest.

I checked, double-checked and triple-checked the plates, boundaries and motions, and I cannot find anything substantially wrong with them. I hope you cannot either . Here's the new tectonics map:



These important changes in Rautah's tectonics meant that I also had to rework the ocean currents. This is the new version:



Of course, all comments are welcome. I think I will let tectonics and ocean currents rest for a while now and concentrate on wind, rainfall and climate. See how that goes...

Cheers - Akubra

[ascanius]

The only thing I noticed is Sayali plate looks like it should be going in the opposite direction away from the divergent boundary. Other than that it looks good. I really like the southwest region a lot. Overall I think you did a very good job. Keep up the great work.

[Pixie]

Well, I was about to write that everything looked perfect... then I read the post by ascanius. Yep, that looks like it should have the arrow pointing opposite.

As for the rest, yes, it is perfect to my eye. Ready for the next step. Word of advice: you will need some for of heightmap, but don't get over detailed as that is a task to take ages. Set just 4 or 5 different levels of altitude - it will be enough.

[Akubra]

@ ascanius: Thanks for spotting that! I have corrected my mistake on the local map on my computer. It's just a small update, so for the moment I'm not going to upload that version here. Yes, the southwest region does look promising, doesn't it (even though it also looks quite complicated...)

@ Pixie: Thanks for the advice! Right now I'm working on a rough height map, and I'm really into it now. Before posting the climate map, I'll post that height map, to be sure I can use it as a base for the climate map. I'm really wondering what that will look like!

Cheers - Akubra

[groovey]

Congrats Akubra, on being done with your tectonics. What a relieve it must be. Glad that you can move on too, and looking forward to see your take on a height-map.

[Akubra]

Hi folks, during the past few days I have been working on a height map as a preparation for a climate map. It's meant to be a purely functional map - its sole purpose is to get information across.

There are 6 height levels: 1 shade of green, 4 shades of grey and white. These are the altitude ranges they indicate:
- green: < 1500 m.
- darkest grey : 1500 - 3000 m.
- next lighter grey : 3000 - 4500 m.
- next lighter grey : 4500 - 6000 m.
- next lighter grey : 6000 - 7500 m.
- white : > 7500 m.

I imagine the highest point of the planet to be slightly higher than 10000 m. above sea level.

To make it a little clearer, here are two maps: one showing the tectonic plate boundaries over the altitude shades and one without the tectonics.



A few questions:
- Do you see any inconsistencies between the tectonics and the mountains/ranges/plateaus formed by them?
- What about the locations and heights of mountains/ranges/plateaus formed by earlier tectonic forces (i.e. those away from the current tectonic boundaries)? In general I have made them lower and with a gentler slope to indicate their age.
- What about the amount of ranges, their sizes and the areas occupied by the different altitudes? Too little, too much, or about the right amount/size?
- I wasn't sure what to do with divergent boundaries on land. I added small, low to medium heighth volcanic ranges (not higher than 4500 m. in general) and mostly elongated lakes. Is that the way to go?
- Any other issues I didn't consider?

I may still add 2 or 3 islands on divergent boundaries located in oceans. These islands will be about the size of Iceland or smaller and their high points will not be over 3000 m.

I'll slowly start drawing the rain patterns based on this map, and hopefully I won't have to correct too much.

Thanks for your feedback!

Cheers - Akubra

[groovey]

As usual, I'm afraid I can't give expert input. Actually, I'm looking forward to hear what the others have to say about it so I can learn a thing or two, because I'd love to do a similar thing for mine.

I do find the system to convey the altitude info useful and clear.

Since the colors indicate altitudes and not simply mountains, they look alright to me.

I know the map is just for info for the climate map, so you'd think about this sort of thing then, but did you have in mind the tropics/subtropics when placing old mountain ranges/altitude, since said tropics are prone in Earth to be kind of desertic and so have a lot of erosion, I ask as a noob, I'm not sure if that's something you have to worry about?


What was your logic for placing the old mountain ranges? Were they simply placed randomly where they fit or you wanted them to be? This is how I do it but I'm not sure if there are rules about it.

The big lake on the top left, how did it came to be? Not by a current divergent boundary, so is it explained by tectonics? By the "closing" of one land bit against another in the past, or how?

[Akubra]

Thanks for your input groovey.

Some answers for you:

• No, I didn't take into account the latitude when placing mountains. Like you, I don't know if I should. You have a point when saying that deserts erode mountains (wind and sand), but I suspect other latitudes have other kinds of erosion (water, ice expanding). So does one kind of erosion go faster than the other? No idea.
• I placed the old mountain ranges rather randomly where I thought it would be nice to have mountains. The only aspect I took into account was the distance between the coast and the continental shelf (for coastal mountains): if they were close together I gave the mountains a steep slope, if they were far apart I gave them a gentler slope.
• Ah, the big lake! I had to have a really, really big lake - bigger than the Caspian Sea. The problem was where to put it. I figured that it could be placed where it was surrounded by high mountains and/or large plateaus with lots of rivers running off them (especially off the huge plateau to the lake's east). The lake would be in a depression with slightly higher land to its north and with an outlet to the ocean in the west. But, as always, my logic may be flawed...

Cheers - Akubra

[Pixie]

,
Hi Akubra.

Here's some input. I'm using your questions to organize the points.

A few questions:
- Do you see any inconsistencies between the tectonics and the mountains/ranges/plateaus formed by them?

I'd prolong the land in the boundary between Sira and Lomo plates. That mountain range would be prolonged southwards, creating a peninsula, and a north-south oriented range, in tune with the boundary.

- What about the locations and heights of mountains/ranges/plateaus formed by earlier tectonic forces (i.e. those away from the current tectonic boundaries)? In general I have made them lower and with a gentler slope to indicate their age.

Fine, mostly. The only one I think less plausible is the coastal range in Arumanthi. That looks like an old plate (even its oceanic crust is old), so the range would have eroded - that sediment runs to the coast, making it wider and the continental shelf in there should also be wide.

- What about the amount of ranges, their sizes and the areas occupied by the different altitudes? Too little, too much, or about the right amount/size?

This is the detail you still need to work on (in my humble opinion!).
In this you made a mistake I was also making in my early elevation maps. You have way too much land above 2000/3000 m. Have a look at his map - its choice of colors really makes the land above 3500 m stand out. On Earth, extreme highand happens much less than in your world. Old ranges have been eroded so much that they hardly reach the 3000m and they would also be very irregular in shape.

- I wasn't sure what to do with divergent boundaries on land. I added small, low to medium heighth volcanic ranges (not higher than 4500 m. in general) and mostly elongated lakes. Is that the way to go?

The lakes between Ghaon and Yama would be in elevated land. Whenever you get a divergent boundary inland, the rise of magma forces the ground to lift. If you look at Earth, the great rift in Africa is surrounded by highlands.

I may still add 2 or 3 islands on divergent boundaries located in oceans. These islands will be about the size of Iceland or smaller and their high points will not be over 3000 m.

Go ahead. I can sea some oceanic islands in Taikaram and Akua plates being great for early navigators/explorers.